System and method for patient medical care initiation based on implantable medical device data with the aid of a digital computer

ABSTRACT

An implantable medical device is disclosed. A housing includes a hollow body forming a first electrode on an outer surface with end caps affixed to opposite ends, one end cap forming a second electrode. A microcontroller circuit is provided and includes a microcontroller operable under program instructions stored within a non-volatile memory device. An analog front end is interfaced to the electrodes to sense electrocardiographic signals. A transceiver circuit is operable to wirelessly communicate with an external data device. The program instructions define instructions to continuously sample the electrocardiographic signals into the non-volatile memory device and to offload the non-volatile memory device to the external data device. A diagnostic overread of the samples can be performed using medical diagnostic criteria and medical care initiated with one of pre-identified care providers based on the overread.

CROSS-REFERENCE TO RELATED APPLICATION

This non-provisional patent application is a continuation of U.S. patentapplication Ser. No. 16/929,390, filed on Jul. 15, 2020, pending (the“application Ser. No. 16/929,390”), the disclosure of which isincorporated by reference. The application Ser. No. 16/929,390 claimspriority under 35 U.S.C. § 119(e) to U.S. Provisional Patentapplication, Ser. No. 62/874,086, filed Jul. 15, 2019 and U.S.Provisional Patent application, Ser. No. 62/962,773, filed Jan. 17,2020, pending, the disclosures of which are incorporated by reference.This application Ser. No. 16/929,390 is also a continuation-in-part ofU.S. patent application Ser. No. 16/926,381, filed Jul. 10, 2020pending, which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent application, Ser. No. 62/873,754, filed Jul. 12,2019, U.S. Provisional Patent application, Ser. No. 62/874,086, filedJul. 15, 2019, U.S. Provisional Patent application, Ser. No. 62/873,740,filed Jul. 12, 10 2019, U.S. Provisional Patent application, Ser. No.62/962,773, filed Jan. 17, 2020, and is further a continuation-in-partof U.S. patent application Ser. No. 16/919,626, filed on Jul. 2, 2020,pending, which claims priority under 35 U.S.C. § 119(e) to U.S.Provisional Patent application, Ser. No. 62/870,506, filed Jul. 3, 2019,the disclosures of which are incorporated by reference.

FIELD

This application relates, in general, to health and medical apparatusesfor sensing and recording the physiology of a living body and, inparticular, to a system and method for patient medical care initiationbased on implantable medical device data with the aid of a digitalcomputer.

BACKGROUND

Patient physiology is one of the four cornerstones of modern diagnosticmedicine, which defines the structured process routinely employed byphysicians and other medical professionals (henceforth, simply“physicians”) to determine the nature and cause of patient healthconcerns and problems, and physicians need data on patient physiologythat is timely, accurate, and reliable to provide effective health care.Through the diagnostic medicine process, a physician will make findingsof possible diagnoses that can explain or match a patient's signs andsymptoms in terms of a disease or medical condition, which therebyenables the physician to formulate a plan of treatment and follow-upcare.

Medical diagnosis includes evaluating patient physiology, whichdescribes the vital functions of the patient's anatomical structure,that is, the living body and its organs. A patient's physiology isdetermined through medical diagnostic procedures that include performingmedical tests and, when available, reviewing patient data that has beencollected through monitoring, although the data should first becorrelated to patient symptoms to be of relevant diagnostic value.

Sporadic conditions present a special challenge because diagnostic testsperformed in a physician's office may prove ineffective if the sporadiccondition fails to present while the test is being performed. Sporadicconditions may be due to chronic or acute cause and can includetransient signs, such as erratic heartbeat, muscle or nerve spasms, orhypoglycemia (or hyperglycemia) that may be accompanied by discernablesymptoms. The unpredictable nature of sporadic conditions often makesthe capturing of physiological data a matter of good timing. If thesporadic condition fails to occur during the course of a medical test,no physiological data, and therefore no diagnostic insight, is obtained.

In response, physicians have turned to ambulatory monitoring, whichutilizes sensors placed cutaneously on or implanted within a patient'sbody that are attached to a recorder to provide physiological datacapture while the patient goes about daily life. Ambulatory monitorsinclude Holter monitors for electrocardiographic (ECG) monitoring,ambulatory blood pressure monitors (ABPM) for collecting blood pressuredata at periodic intervals, and continuous glucose monitors that collectblood glucose data. Through ambulatory monitoring, physiological datamay be captured and recorded continuously, upon demand for subsequentretrieval and evaluation, or might be recorded and reported in real ornear real time, provided that the recorder is equipped with remote datacommunications capabilities using, for instance, cellularcommunications.

Ambulatory monitors that are either wholly implanted inside thepatient's body or which use implanted sensors will generally providecleaner physiological data relatively free of environmental noise andeffects, especially when compared to data captured cutaneously. However,implantation is, by definition, invasive to some degree and carries morerisk than cutaneous or external forms of ambulatory monitoring.Moreover, at least in part in light of the significance, complications,and expense of implantation, implanted forms of ambulatory monitors arealso expected to be capable of operating over an extended period oftime, so battery depletion must be considered to ensure sufficientservice life. Thus, continuous recording of every heartbeat is notpossible in conventional implantable ambulatory monitors due to powerconsumption and hard limits of onboard processing and storage, ascontinuous per-heartbeat monitoring places significant demands on theseresources, which are strictly limited in an implantable device.

Typically, implanted forms of ambulatory monitors provide a single formof sensing into a patient's body using purpose-built hardware that willserve over the lifetime of the device, such as electrocardiographicelectrodes. The associated recorder is similarly deployed to capturephysiology through the sensing hardware by operating under a programmingset that must accommodate an entire potential patient population. Insome cases, additional programming complexity may be required to cover aminority of patients that nevertheless must be included in theprogramming set, albeit at the expense of conceivably dominating anengineering solution by requiring additional storage and computationalresources.

Moreover, in conflict with the decision to provide a single form ofsensing, an ambulatory monitoring environment is not static. A patient'sbody could (and likely will) change over time during the course oftreatment, necessitating a different monitoring strategy or type ofsensor for other forms of physiology. Notwithstanding, physicians areeffectively limited to the hardware on-hand at the time of implanting.Such design tradeoffs, such as having only a single form of sensing andreliance upon a general purpose programming set, limit the abilities ofimplanted forms of conventional ambulatory monitors. New sensorycapabilities cannot be added without implanting new sensing hardware,plus each new sensor must somehow be interfaced to the recorder, whichwill need to be able to handle the new sensor in terms of data capture,processing, and storage. Additional sensory capabilities may alsoadversely effect battery life, which can be of particular concern if therecorder lacks recharging capabilities and the intended service life ofthe implantable device could be negatively impacted.

Therefore, a need remains for an implanted form of ambulatoryphysiological monitor that offers per-heartbeat monitoring with flexibleand extensible monitoring capabilities in terms of sensory capabilities,scope of device programming, and service life, without having to implantadditional hardware.

SUMMARY

A configurable hardware platform for health and medical monitoring ofphysiology is housed within a hermetically sealed implantable medicaldevice (IMD). Physically, the IMD has a generally tubular shape thatincludes a central tubular body with rounded semi spherical end caps.When configured to measure electrocardiographic signals, the centraltubular body and one of the semi spherical end caps function aselectrode dipoles. The semi spherical end cap is electrically conductiveyet electrically insulated from the central tubular body. As well, theoutside surface of the central tubular body is partially electricallyinsulated, generally on the surface closest to the electricallyconductive semi spherical end cap to form a non-electrically conductiveinversion with only the outside surface distal to that semi sphericalend cap being exposed.

When placed within the central tubular body, a flexible circuit boardforms three aspects of a microcontroller circuit assembly thatrespectively define a receiving coil for inductive charging and optionalcommunication, a high frequency antenna for radio frequency (RF) dataexchange, and a flexible circuit board containing a microcontroller anddevice circuitry. An onboard power source that includes a rechargeableenergy cell, battery, or supercapacitor is also placed within thetubular body to one end of the flexible circuit board and, optionally,in electrical contact through a protection circuit with the electricallyconductive semi spherical end cap, thereby serving as an electricalfeedthrough to the flexible circuit board. The power source may berecharged through a charging and conditioning circuit interfaced withthe microcontroller using a non-contact method, such as inductivecharging, resonant charging, energy harvesting, thermal gradientcharging, ultrasonic charging, RF-based charging or charging by ambientor driven motion.

The IMD can provide continuous monitoring of the patient on aheartbeat-by-heartbeat basis. The monitoring data is regularly offloadedthrough live transmission or delayed transmission, which may occur, forinstance, two days or longer following recordation, or live monitoring.The offloaded monitoring data is analyzed at a datacenter, where theprocessing constraints imposed by the computational and resource limitsof the IMD are not a hindrance. Additionally, the IMD is equipped withone or more physiological or non-physiological sensors that can beselectively activated over the implantation lifetime to tailor themonitoring of the patient to ongoing diagnostic needs. The physiologicalsensors non-exhaustively include ECG, temperature, oxygen saturation,respiration, blood glucose, and sensors which detect movement, position,or acceleration.

In one embodiment, a system and method for patient medical careinitiation based on implantable medical device data with the aid of adigital computer are provided. The system includes an implantablemedical device, a download station, and an at least one computer. Theimplantable medical device, includes a housing on which a first and asecond electrode are formed; and a microcontroller circuitcircumferentially provided within the housing and including amicrocontroller operable under program instructions stored within anon-volatile memory device, further including: an analog front endelectrically interfaced to the first and the second electrodes andoperable to sense electrocardiographic signals; and a transceivercircuit operable to wirelessly communicate with a download station; andthe program instructions defining instructions for the microcontrollerto continuously sample the electrocardiographic signals into thenon-volatile memory device and to offload the non-volatile memory to thedownload station via the transceiver circuit. The download station isconfigured to receive the samples from the transceiver circuit. Theleast one computer includes a database configured to store the receivedsamples and medical diagnostic criteria and a processor and a memoryconfigured to store code executable by the processor, the processorconfigured to: generate a diagnostic overread of the samples using themedical diagnostic criteria; and initiate medical care of the patientwith one or more pre-identified care providers based on the overread.

Another embodiment provides an implantable medical device. A cylindricalhollow body forms a first electrode on an outer surface. A firstspherical end cap is attached on one end of the hollow body. A secondspherical end cap is attached on an other end of the hollow body andforms a second electrode on an outer surface. Electronic circuitry ishoused within the hollow body. A microcontroller is operable underprogram instructions contained in microcode stored within a non-volatilememory device. A physiological sensor is operable to sense physiologicaldata and is electrically interfaced to the microcontroller. An analogfront end is electrically interfaced to the first and the secondelectrodes and the microcontroller and operable to senseelectrocardiographic signals. A transceiver circuit is electricallyinterfaced to a high frequency antenna housed within the secondspherical end cap and the microcontroller and is operable to wirelesslycommunicate with an external data device. A receiving coil is formed aspart of a non-contact charging circuit. The program instructions areoperable to instruct the microcontroller to continuously sample theelectrocardiographic signals and the physiological data at set timesinto the non-volatile memory device and to offload the non-volatilememory device to the external data device via the transceiver circuit. Apower source is housed within the hollow body and is electricallyinterfaced to the non-contact charging circuit. The power source isoperable to power the microcontroller.

Yet another embodiment provides an implantable medical device. A maincylindrical body defines an axial bore extending longitudinally over thelength of the main cylindrical body and exposes an electricallyconductive area defining a first electrode on at least part of the outersurface of the main cylindrical body. A protective spherical end cap isfixedly disposed on one end of the main cylindrical body and defines aninterior cavity. The protective spherical end cap further exposes anelectrically conductive area defining a second electrode on at leastpart of the outer surface of the protective spherical end cap. Anantenna spherical end cap is fixedly disposed on one end of the maincylindrical body and defines an interior cavity with a high frequencyantenna housed within. A printed circuit board is housed within the maincylindrical body. Electronic circuitry includes a physiological sensoroperable to sense physiological data. The electronic circuitry alsoincludes an analog front end electrically interfaced to the first andthe second electrodes and operable to sense electrocardiographicsignals. A transceiver circuit is electrically interfaced to the highfrequency antenna and is operable to wirelessly communicate with anexternal data device. A microcontroller is operable under programinstructions contained in microcode stored within a non-volatile memorydevice and is electrically interfaced with a physiological sensor, theanalog front end, and the transceiver circuit. The microcontroller isoperable under the program instructions to record the physiological dataat set times and the electrocardiographic signals continuously into thenon-volatile memory device and to offload the electrocardiographicsignals from the non-volatile memory device to the external data device.A receiving coil is formed on an extended surface of the printed circuitboard that is adapted to be circumferentially disposed about theelectronic circuitry and is provided as part of a non-contact chargingcircuit. A power source comprising a rechargeable energy cell housedwithin the main cylindrical body and electrically interfaced with thecharging circuit to power the electronic circuitry.

The configurable hardware platform provides several advantages overconventional designs, including rapid recharging, a flexible andextensible hardware platform, the ability to provide full and completedisclosure of physiological recording data (in contrast to binned,averaged, event-based or other forms of telemetric disclosure),continuous monitoring, store and forward functionality, and the abilityto serve as an extended or lifetime monitor.

Still other embodiments will become readily apparent to those skilled inthe art from the following detailed description, wherein are describedembodiments by way of illustrating the best mode contemplated. As willbe realized, other and different embodiments are possible, and theembodiments' several details are capable of modifications in variousobvious respects, all without departing from their spirit and the scope.Accordingly, the drawings and detailed description are to be regarded asillustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an outer perspective view showing an IMD that houses aconfigurable hardware platform for physiological monitoring of a livingbody in accordance with one embodiment.

FIG. 2 is an outer perspective view showing the central tubular body ofthe IMD of FIG. 1.

FIG. 3 is a side perspective view showing the semi spherical end cap(“Radome”) of the IMD of FIG. 1.

FIG. 4 is a side perspective view showing the electrically conductivesemi spherical end cap (“Protectrode”) of the IMD of FIG. 1.

FIG. 5 is an inside perspective view showing the interior of the end capof the “Protectrode” of FIG. 4.

FIG. 6 is an inside perspective view showing the interior of the end capof the “Protectrode” of FIG. 4.

FIG. 7 is an inside perspective view showing the interior of the fullyassembled “Protectrode” of FIG. 4.

FIG. 8 is an exploded perspective view showing the components of the“Protectrode” of FIG. 4.

FIG. 9 is a top plan view of a flexible circuit board for use in the IMDof FIG. 1 in a flat, unfolded form.

FIG. 10 is a three-quarters perspective view of the flexible circuitboard of FIG. 9 in a semi-folded configuration.

FIG. 11 is an outer perspective view showing an IMD that houses aconfigurable hardware platform for physiological monitoring of a livingbody in accordance with a further embodiment.

FIG. 12 is a block diagram showing the microarchitecture of the IMD ofFIG. 1.

FIG. 13 is a flow diagram showing a method for continuously monitoringelectrocardiography for use in the IMD of FIG. 1.

DETAILED DESCRIPTION Related Applications

This non-provisional patent application is related to incommonly-assigned U.S. Pat. No. 9,545,204, issued Jan. 17, 2017 toBishay et al.; U.S. Pat. No. 9,730,593, issued Aug. 15, 2017 to Felix etal.; U.S. Pat. No. 9,717,432, issued Aug. 1, 2017 to Felix et al.; U.S.Pat. No. 9,775,536, issued Oct. 3, 2017 to Felix et al.; U.S. Pat. No.9,433,380, issued Sep. 6, 2016 to Bishay et al.; U.S. Pat. No.9,655,538, issued May 23, 2017 to Felix et al.; U.S. Pat. No. 9,364,155,issued Jun. 14, 2016 to Bardy et al.; U.S. Pat. No. 9,737,224, issuedAug. 22, 2017 to Bardy et al.; U.S. Pat. No. 9,433,367, issued Sep. 6,2016 to Felix et al.; U.S. Pat. No. 9,700,227, issued Jul. 11, 2017 toBishay et al.; U.S. Pat. No. 9,717,433, issued Aug. 1, 2017 to Felix etal.; U.S. Pat. No. 9,615,763, issued Apr. 11, 2017 to Felix et al.; U.S.Pat. No. 9,642,537, issued May 9, 2017 to Felix et al.; U.S. Pat. No.9,408,545, issued Aug. 9, 2016 to Felix et al.; U.S. Pat. No. 9,655,537,issued May 23, 2017 to Bardy et al.; U.S. Pat. No. 10,165,946, issuedJan. 1, 2019 to Bardy et al.; U.S. Pat. No. 10,433,748, issued Oct. 8,2019, to Bishay et al.; U.S. Pat. No. 10,667,711, issued Jun. 2, 2020,to Felix et al.; U.S. Pat. No. 9,619,660, issued Apr. 11, 2017 to Felixet al.; U.S. Pat. No. 10,463,269, issued Nov. 5, 2019 to Boleyn et al.;U.S. Pat. No. 9,408,551, issued Aug. 9, 2016 to Bardy et al.; U.S.Patent Application Publication No. 2019/0069800, published Mar. 7, 2019to Bardy et al.; U.S. Patent Application Publication No. 2019/0069798,published Mar. 7, 2019 to Bardy et al.; U.S. Patent ApplicationPublication No. 2019/0117099, published Apr. 25, 2019 to Bardy et al.;U.S. Patent Application Publication No. 2019/0099105, published Apr. 4,2019 to Felix et al.; U.S. Pat. No. 10,624,551, issued Apr. 21, 2020 toBardy et al.; U.S. Pat. No. 10,251,576, issued Apr. 9, 2019 to Bardy etal.; U.S. Pat. No. 9,345,414, issued May 24, 2016 to Bardy et al.; U.S.Pat. No. 10,433,751, issued Oct. 8, 2019 to Bardy et al.; U.S. Pat. No.9,504,423, issued Nov. 29, 2016 to Bardy et al.; U.S. Patent ApplicationPublication No. 2019/0167139, published Jun. 6, 2019 to Bardy et al.;U.S. Design Pat. No. D717955, issued Nov. 18, 2014 to Bishay et al.;U.S. Design Pat. No. D744659, issued Dec. 1, 2015 to Bishay et al.; U.S.Design Pat. No. D838370, issued Jan. 15, 2019 to Bardy et al.; U.S.Design Pat. No. D801528, issued Oct. 31, 2017 to Bardy et al.; U.S.Design Patent No. D766447, issued Sep. 13, 2016 to Bishay et al.; U.S.Design Pat. No. D793566, issued Aug. 1, 2017 to Bishay et al.; U.S.Design Pat. No. D831833, issued Oct. 23, 2018 to Bishay et al.; and U.S.Design patent application Ser. No. 29/612,334, entitled: “Extended WearElectrode Patch,” filed Jul. 31, 2017, pending; U.S. patent applicationSer. No. 16/919,626, filed on Jul. 2, 2020, entitled “SubcutaneousP-Wave Centric Insertable Cardiac Monitor With Energy HarvestingCapabilities,” pending; and U.S. patent application Ser. No. 16/926,381,filed Jul. 10, 2020, entitled “System and Method for Remote ECG DataStreaming in Real-Time,” pending, the disclosures of which areincorporated by reference.

Overview

A configurable hardware platform for health and medical monitoring ofphysiology is housed within a hermetically sealed, implantable medicaldevice (IMD). The IMD provides an implanted form of ambulatoryphysiological monitor that offers per-heartbeat monitoring with flexibleand extensible monitoring capabilities. The IMD is designed to beimplanted within a living body and to operate over an extended timeperiod while monitoring different types of patient physiology, possiblyat different times and in different ways.

The IMD can record every heartbeat, perform live transmission or delayedtransmission, which may occur, for instance, two days or longerfollowing recordation, or live monitoring. When every heartbeat isrecorded and sent, the platform does not require an analysis algorithmonboard; rather, the analysis algorithm could be implemented at adatacenter or on a cell phone to do the heavy data processing byutilizing the better computing resources available on those platforms.The IMD is equipped with one or more physiological sensors thatnon-exhaustively include ECG, temperature, pulse oximetry, oxygensaturation, respiration, blood glucose, blood pressure, and drug levelsor any appropriate measure of disease. In a further embodiment, the IMDcan also monitor non-physiological data when the IMD is equipped with anappropriate type of sensor, such as posture as derived from datameasured by an actigraphy sensor, accelerometer or inertial motionsensor. Other types of sensors and forms of physiology andnon-physiological data capture are possible, such as cardiac effortlevel, thoracic impedance, and sound recording, including ultrasonic andsub-sonic sound recording.

The degree of surgical invasiveness required to implant the IMD dependsupon the intended situs within the body, which is at least in partdictated by the desired range of physiology to be monitored. Forinstance, electrocardiographic monitoring of the heart that emphasizesthe propagation of low amplitude, relatively low frequency contentcardiac action potentials, particularly the P-waves that are generatedduring atrial activation, can be efficaciously performed by implantingthe IMD in a subcutaneous situs located axially and slightly to eitherthe left or right of the sternal midline in the parasternal region ofthe chest. This type of subcutaneous implantation can be performed in aphysician's office using a specialized implantation instrument thatincludes a trocar to incise the skin and form a subcutaneous tunnel, anda cannula through which the IMD is guided into place, after which theimplantation instrument is withdrawn and the surgical incision isclosed.

Specific details of the IMD's housing, electronic and support circuitry,power source, and microarchitecture will now be discussed.

Housing

Physically, the IMD has a generally cylindrical shape that includes acentral tubular body with rounded semi spherical end caps, althoughother shapes and configurations are possible. In a further embodiment,one or both of the semi spherical end caps may be replaced pointed orsemi-pointed tips to ease insertion into the body. FIG. 1 is an outerperspective view showing an IMD 10 that houses a configurable hardwareplatform for physiological monitoring of a living body in accordancewith one embodiment. The IMD 10 includes three primary assemblies. Themain middle section of the IMD 10 is a central body 11 that can beformed from a medical grade titanium or similar medicalimplantation-safe material. The central body 11 has a tubular orcylindrical shape that defines an axial bore, which provides a hollowinterior cavity that is open on both end caps running longitudinallyover the length of the central body 11. Other shapes having non-circularor non-spherical shapes are possible. Rounded semi spherical end caps 12and 13 are welded or affixed to the central body 11 to form ahermetically sealed device housing. The end caps 12 and 13 can be formedin other shapes, such as pointed or semi-pointed tips.

The central body 11 houses a flexible circuit board, a low frequencyresonant charger antenna to facilitate device recharging, and an onboardpower source generally consisting of a rechargeable energy cell,battery, or supercapacitor. One of the semi spherical end caps, known asthe “Protectrode” 12, serves a dual purpose as an electrode and housingfor patient and device protection components. The other semi sphericalend cap, known as the “Radome” 13, houses a high frequency antenna usedfor transmitting data over an RF link, using, for instance, Bluetooth orWiFi. Additionally, the “Radome” 13 could be used to house an inductiveantenna and inductive link. The RF link may also be used for devicecalibration and configuration. In a further embodiment, the “Radome” 13can also house physiological sensors, such as pulse oximetry and bloodpressure. In a further embodiment, the optically clear “Radome” 13 mayallow light or other forms of radiation to be received and transmittedthrough to passively facilitate collection of other vital signs, such aspulse oximetry and blood pressure. In a still further embodiment, fiberoptics or lenses implanted into the “Radome” 13 may facilitatecollection of vital signs by sensors housed elsewhere. The IMD 10 has anoverall length of approximately 5.5 cm to 8.5 cm with an outer diameter,measured across the central body 11, of approximately 5-8 mm and a wallthickness of approximately 0.3 mm; however, other dimensions, includingoverall length, wall thickness, and outer diameter, are possibledepending upon both the electronic circuitry and power source that needto be housed within and the types and numbers of physiological andnon-physiological sensors.

In a further embodiment, the IMD 10 can be filled with a gas, such asargon or other inert gas. In particular, argon gas is conventionallyused when welding titanium components and, when oxygen-purged into theinterior of the IMD 10, further serves to preserve the electricalcomponents and facilitate device longevity. In addition, supportingstructure, such as an acrylic rod, can be used as an internal spacer tohelp keep the internal components in proper position.

In one embodiment, the central body 11 and the “Protectrode” 12 can bemicro bead blasted to respectively increase the roughness of the centralbody 11 to improve silicone or Parylene bonding and to increase thesurface area of the “Protectrode” 12 for better signal quality. Atitanium nitride coating could also be applied to dramatically increasethe surface area of the device.

The conductive surface 18 is formed by partially insulating the outsidesurface of the central body 11 using a non-electrically conductive,insulating surface treatment or coating (“insulating coating”) 19. Theinsulating coating 19 is generally applied on the outer surface closestto the “Protectrode” 12, which maximizes the electrode dipole spacing.In one embodiment, the insulating coating 19 can be a chemical vapordeposited poly polymer, such as Parylene C. In a further embodiment, theinsulating coating 19 can be a silicone polymer-based (polysiloxanes)coating. Alternatively, both forms of coatings, poly polymer andsilicone polymer, could be employed. Poly polymers exhibit superiormoisture resistance and insulation resistance properties, but aresusceptible to damage from scratches and scrapes. Silicone polymercoatings form a durable protective layer and, when applied over a polypolymer coating, such as Parylene C, can protect the underlying coatingfrom scratches and scrapes during insertion, repositioning, or removalof the IMD 10.

The end 22 of the central body 11 closest to the conductive surface 18interfaces to the “Radome” 13. In one embodiment, the high frequencyantenna is a separate component that is contained within the “Radome”13. Here, the high frequency antenna can be held in place by filling thecavity of the “Radome” 13 with a filler material, such as acrylic,urethane, glass, or similar material, and the high frequency antennal isinterfaced to a flexible circuit board via an electrical contact 20 thatcan be soldered or bonded to the high frequency antenna. In a furtherembodiment, the high frequency antenna is formed on a foldable “ear”section of the flexible circuit board and routed into the “Radome” 13assembly. In one embodiment, when configured to measureelectrocardiographic signals, the “Protectrode” 12 and an exposed,conductive surface 18 of the central body 11 function as an electrodedipole. Other forms of electrode dipoles are possible. FIG. 3 is anouter perspective view showing the central body 11 of the IMD 10 ofFIG. 1. The end cap 14 of the “Protectrode” 12 forms one electrode. Anexposed, conductive surface 18 of the central body 11 distal to the“Protectrode” 12 forms the other electrode. The metallic case of thepower source provides an electrical feedthrough from the “Protectrode”12 to a flexible circuit board, thereby simplifying construction.

“Radome”

Informally, the non-electrically conductive semi spherical end cap formsa “Radome” (radar dome) 13 that serves as a housing for a high frequencyantenna used for RF data exchange. FIG. 2 is a side perspective viewshowing the semi spherical end cap (“Radome”) of the IMD 10 of FIG. 1. Ahigh frequency antenna 34 for data exchange is housed within the“Radome” 13. Note that more than one high frequency antenna could beincluded. The “Radome” 13 is an assembly that includes an electricallyinsulated semi sphere 17 formed from a medical implantation-safe gradematerial, such as acrylic, glass, ruby crystal, or ceramic, and ametallic weld ring 20 formed from a medical grade titanium or similarmedical implantation-safe metal. These parts are bonded together usingpressure fitting, brazing, laser welding, or electron beam welding. In afurther embodiment, the high frequency antenna is defined as part of aflexible circuit board or folded metal shape, folded wire, or othersimilar structure, as further described infra.

“Protectrode”

Informally, the electrically conductive semi spherical end cap forms a“Protectrode” (feeder electrode) 12 that serves a dual purpose as anelectrode and as housing for patient and device protection components.FIG. 4 is a side perspective view showing the electrically conductivesemi spherical end cap (“Protectrode”) of the IMD 10 of FIG. 1. The“Protectrode” 12 is an assembly that includes an electrically conductivesemi sphere 14 formed from a medical grade titanium or similar medicalimplantation-safe conductor, an insulator ring 15 formed from a medicalimplantation-safe grade material, such as acrylic, glass, ruby crystal,or ceramic, and a metallic weld ring 16, which can include a chamferededge 23 to facilitate welding to the central body 11, formed from amedical grade titanium or similar medical implantation-safe metal. Theseparts are bonded together with heat fitting, press fitting, brazing,epoxy adhesive, silicon adhesive or other similar bonding agent.

The construction details of the “Protectrode” 12 will now be discussed.FIG. 5 is an inside perspective view showing the interior of the end cap14 of the “Protectrode” 12 of FIG. 4. In one embodiment, a set ofconcave dimples 26 is formed along an inside shelf surface of the endcap 14. The dimples 26 increase surface area and thereby facilitateadhesion of the end cap 14 to the insulator ring 15, they also resistcircular rotation. FIG. 6 is an inside perspective view showing theinterior of the end cap 14 of the “Protectrode” 12 of FIG. 4. Acircumferential groove 25 is longitudinally defined within a cavity 24inside the end cap 14. The groove 25 provides a mounting location for acircuit board 27. The edges of the circuit board 27 are plated with aset of electrically conductive coatings 28 that include, starting fromthe circuit board 27 and proceeding outward, copper, nickel (thicklyapplied), palladium (thinly applied), and gold (of medium thickness),although other materials and combinations of layers are possible. Theconductive coatings 28 are necessary to ensure against a galvanicreaction between the copper traces of the circuit board 27 and thetitanium shell of the end cap 14. The “Protectrode” may be filled withepoxy or a similar material such as silicon to increase strength anddielectric breakdown properties and provide resistance to corrosion. Thefiller also will bond with the insulator when the insulator is made outof a brittle material such as ruby, glass or ceramic. The adhesive willhold in place the brittle material should the material fracture duringan extreme impact event, such as a car crash.

FIG. 7 is an inside perspective view showing the interior of the fullyassembled “Protectrode” 12 of FIG. 4. The edges of the circuit board 27contact the “Protectrode” 12 along the groove 25. The edges of thecircuit board 27 contact the “Protectrode” 12 in two places, in thegroove 25 along the end cap 14 and in the groove 25 along the metallicweld ring 16 (the groove 25 is formed along only one side of themetallic weld ring 16, but could be formed along both sides).

FIG. 8 is an exploded perspective view showing the components of the“Protectrode” of FIG. 4. The circuit board 27 includes a protectioncircuit 35 for the electrode dipole. The insulator ring 15 electricallyisolates these two contact points, thereby allowing the protectioncircuit 35 to interface with both electrodes, that is, the “Protectrode”12 and the conductive surface 18.

Flexible Circuit Board

The primary electrical structure of the IMD 10 is made out of a singleflexible circuit board, which effectively eliminates many inter-circuitboard connections and the delicate construction required to create them.

Folded Shape

The flexible circuit board 30 resembles a piece of origami paper that isfolded into final shape, which is expected to increase device longevityand reliability by simplifying the design and eliminate thecommonly-encountered failure points found in traditional designs. FIG. 9is a top plan view of a flexible circuit board 30 for use in the IMD 10of FIG. 1 in a flat, unfolded form. The flexible circuit board 30 isformed out of a single piece of flexible circuit board substratedefining a flexible circuit board 30 for placement of themicrocontroller and device circuitry, a pair of vertically disposedfoldable “ears” 32 provided on opposite ends of the flexible circuitboard 30, and a foldable (or rollable) area 33 that acts as a receivingcoil for inductive power coupling. On one end of the flexible circuitboard 30, a foldable ear 32 connects to a power source and thefeedthrough provided by the power source's case. On the other end of theflexible circuit board 30, the foldable ear 32 either connects to a highfrequency antenna that is a separate component contained within the“Radome” 13 or the foldable ear 32 itself forms the high frequencyantenna 23. The flexible circuit board 30 can include circuit traces onall sides, or multiple layers covered by an insulating layers tomaximize space utilization. In one embodiment, the receiving coil'scircuit traces are copper, although other types of conductive materialscould be used.

FIG. 10 is a three-quarters perspective view of the flexible circuitboard 30 of FIG. 9 in a semi-folded configuration. When placed withinthe central tubular body, the flexible circuit board 30 forms threeaspects 31 of a microcontroller circuit assembly that respectivelydefine a receiving coil 36 for energy capture, a pair of inter-deviceconnecting ears 32, and a printed circuit board 37 containing a lowpower microcontroller and device circuitry operable to execute undermodular micro program control as specified in firmware. The flexiblecircuit board 30 can be folded into a triangular shape 34 or horseshoeshape (not shown) and each of the inter-device connecting ears 32 arefolded angularly inward towards the triangular ends of the triangularshape 34. The foldable area 33 is either folded or rolled around thetriangular shape of the flexible circuit board 30 and ears 32. Othershapes may be possible, including other variations on “ears” orextensions to the flexible circuit board 30.

Receiving Coil

A power receiving coil 36 is formed by folding (or rolling) the foldable(or rollable) area 33 (shown in FIG. 9) circumferentially about thetriangular or horseshoe shape that contains the microcontroller anddevice circuitry. The foldable (or rollable) area 33, however, is longerthan the flexible circuit board 30 and is defined, when installed insidethe IMD 10, to extend for substantially the entire longitudinal lengthof the tubular body 11. The receiving coil 36 uses planar traceconstruction to maximize the capture of magnetic flux and providesinsulation between the positive and negative electrode poles of the IMD10. In further embodiments, signals can be routed from the spherical endcaps through the antenna. As well, additional sensors can be implantedin the antennas.

In one embodiment, the receiving coil 36 that is used for gatheringenergy to recharge the power source is connected to a clamping diodearray and fusible link. In the presence of extreme electromagneticenvironments, the protection diode array will limit the voltage acrossthe antenna protecting the device charging circuitry. If the diode arrayis overwhelmed for a long enough period of time, the fusible link willopen to protect the patient from the effects of device heating due toexcessive charging energy received from the receiving coil. The fusiblelink may optionally be constructed out of a resettable overcurrentdevice, thermally actuated device, or fusible current limiting device.

In a further embodiment, the foldable (or rollable) area 33 is definedto form, when installed inside the IMD 10, a diagonal antenna that (notshown) will limit dead zones by creating a spiral where the two halvesof the receiving coil connect. A standard square-shaped receiving coilcould potentially lead to an RF dead zone in certain orientations. Thediagonal antenna has a wide track and is overlaid, so that there are twooverlapping areas, which should result in efficient flux capture forfields passing through the antenna.

In one embodiment, the high frequency antenna, when formed on a foldableear 32 of the flexible circuit board 30, can be folded in different waysto create a range of antenna shapes. Note that more than one highfrequency antenna could be used. The antenna is completely integratedinto the flex circuit, which eliminates feedthrough that also translatesinto much better energy coupling.

In one embodiment, the receiving coil is sandwiched between the centraltubular body 11, which can be a titanium cylindrical enclosure, and thecase of the power source, described infra, which can also be acylindrical titanium battery case. During inductive charging, eddycurrents are induced in the titanium battery case. The eddy currents canraise the temperature of the IMD 10 and can reduce charge efficiency.This effect can be countered by reflecting the low frequency chargingmagnetic field into the low frequency energy receiving antenna with theincrease in efficiency resulting in less heating. A ferrite coating orferrite sheet can be applied to the outside casing of the power sourceto increase charge transfer efficiency by reflecting energy back intothe receiving coil. Since the energy is reflected, less heating of thepower source will occur during inductive charging due to decreased eddycurrents.

Forming the power receiving coil 36 by folding or rolling the flexiblecircuit board provides several benefits over conventional implantabledevice design. First, the folding or rolling of the flexible circuitboard affords a thin design that facilitates patient comfort by enablingcompact packaging, resulting in an smaller device than would otherwisebe available in a comparably rechargeable design. Second, the wideaspect ratio of the power receiving coil, when compared with to atraditional wire coil, allows a low loss element, thereby decreasingdevice heating. Moreover, the low loss element enables quicker chargingthrough higher energy reception without excessive heating. Third, theunique shape enables injectable implantation technique that are notpossible with traditional planar coils. Finally, the completelyintegrated design of the printed circuit board containing themicrocontroller and related circuitry and the receiving coil simplifiesdevice design, decreases weight, improves device longevity, andincreases patient safety by virtue of requiring fewer parts and nodiscrete interconnections using, for instance, soldered wires or circuittraces.

Power Source and Charging Circuit

A power source that includes an inductively-rechargeable energy cell,battery, or supercapacitor is also placed within the IMD 10 to one endof the flexible circuit board 30 and in electrical contact with theelectrically conductive semi spherical end cap 13, thereby serving as anelectrical feedthrough to the flexible circuit board 30. The powersource may be recharged through a charging and conditioning circuitinterfaced with the microcontroller using a non-contact method, such asinductive charging, resonant charging, energy harvesting, thermalgradient charging, ultrasonic charging, RF-based charging or charging byambient or driven motion including vibration. Low frequency chargingcircuits are most efficient at transmitting energy through solidobjects. When a charging circuit operates, vibrations are induced in thecoils used in the charger as well as surrounding conductive objects.However, these vibrations, if within the human audible hearing range (ora close multiple thereof) create sound.

A traditional charging circuit uses a single frequency to transmitpower. If the frequency or a major harmonic thereof is within theaudible human hearing range, a single tone that humans can find veryannoying could result. To overcome this issue, traditional chargingcircuits operate above the human audible hearing range. However, insteadof using a single frequency for charging, a low frequency chargingcircuit could also modulate the charging waveform at audible frequenciesthat result in a pleasant sound for the user, so as to allow thetechnical benefits of low frequency charging without causing annoyanceto humans.

Modulation of frequencies requires receive and transmit circuitry withhigher bandwidth to accommodate the frequency shifts efficiently. Themodulation can cause decreased circuit Q (“quality”), which can beovercome by using a variable capacitor or other automatic tuning circuitto ensure sufficient resonance as the frequency changes. For example, ifthe frequency changes, tuning may be required to restore satisfactorycoupling. The automatic tuner circuit could predict the value needed toachieve resonance or a high Q factor based on the input frequency, oralternatively could employ a feedback system to self-tune as the inputfrequency changes. The automatic tuner circuit could further be employedto efficaciously control charging to decrease overall charging time.Differences in devices, patients and their environment will modify the Qfactor of the system. An automatic turning circuit can automaticallycompensate for these changes.

In a still further embodiment, a feedback circuit or system could befurther employed to automatically compensate for changes in theenvironment and patient load. The feedback circuit would tune chargingbased on input energy. Alternatively, the feedback circuit method is toknow what is coming and instantly auto tune the charging circuitry basedon the pattern that will be sent shortly to the IMD 10.

The feedback system could also be used to provide positive feedback tothe patient. For instance, the modulation frequency could produce a very“futuristic” sound, such as a low to high frequency ramp, which repeatsat a predetermined interval, or could even play a song, perhaps of thepatient's choosing. Further, the modulation frequency could be used tosignal to the user the state of the device, such as charging, errorcondition, or completion of charging.

Encasement

The power source may optionally be encased in a metallic cylindricalcase that also functions as an electrical feedthrough, where the outsideof the power source case is used as a conductor to the electrodeconnection. Conventional IMDs are typically rectangular or prismatic inshape. A cylindrical shape offer several advantages, including patientcomfort, power source design, accommodations for different types ofantennae, and improved insertability and ease of explant.

The actual electrode contact area forms a hollow dome to absorb anyswelling that might occur during the extremely unlikely event of acatastrophic power source failure. A set of feedthroughs, arranged in apossible pattern of [+/Temp/−/chassis] is provided to provide increasedsafety, reduction of leakage currents and ease of assembly.

In one embodiment, the power source case is electro polished to improvethe ability of the receiving coil 36 to slide over the power source caseduring installation. In a further embodiment, the head of the powersource, that is, the end of the power source that faces outwards awayfrom the flexible circuit board 30 and replaces the “Protectrode”assembly. The head is formed of thin titanium and shaped as a dome toserve as an electrode and provide internal relief for power sourceexpansion if a failure occurs.

Chemistry

In one embodiment, the power source can use lithium titanate (LTO)technology. Alternatively, other power source or battery technologiessuch as Lithium Cobalt Oxide, Lithium Manganese Oxide, Lithium NickelManganese Cobalt Oxide, Lithium Iron Phosphate, Lithium Nickel CobaltAluminum Oxide, Nickel Cadmium or Nickel Meta Hydrate could be employed.

To accommodate complete discharge without oxidation of the power sourcecollector, the copper collector typically found in a power source couldbe replaced by a corrosion resistant metal, such as stainless steel,titanium, gold or platinum. Furthermore, a collector could be made of astandard base metal and plated to increase corrosion resistance. Thiscombination of materials could be copper, nickel, palladium, gold ortitanium, gold, or stainless steel, gold or any appropriate combinationthereof to provide the necessary degree of corrosion resistance and zerovolt life. The surfaces of the materials and platings could be roughenedto increase surface area and provide better charge and dischargecharacteristics.

Scalloped Electrodes

The proximity of the high frequency antenna 34 to the conductive surface18 exposed on the outside surface of the tubular body 11 can, in somecircumstances, pose a risk of ECG signal degradation. FIG. 11 is anouter perspective view showing an IMD 60 that houses a configurablehardware platform for physiological monitoring of a living body inaccordance with a further embodiment. The electrode 61 formed as part ofthe “Protectrode” section of the IMD 60 and the electrode 62 formed onthe outer surface of the tubular body 11 are shaped with scallopedcutouts on their respective inward facing aspects. The electrodeformation minimizes potential parasitic coupling of the electrodes 61and 62 to ground strips that are used for the high frequency antennareturn. In addition, the shape of the “Protectrode” electrode 61increases the performance and durability of the ceramic to titanium weldjoints, when used, to join the “Protectrode” 14 to the tubular body 11.

Microarchitecture

The operation of the IMD 10, including data capture, analysis, andcommunication, is controlled by a programmable microcontroller. FIG. 12is a block diagram showing the microarchitecture 40 of the IMD 10. Themicrocontroller is remotely interfaceable over a wireless radiofrequency (RF) data communications link using the high frequency antenna34 that is housed within the “Protectrode” 14, which enables the IMD 10to provide continuous heartbeat-by-heartbeat monitoring and to beremotely reconfigured or reprogrammed to utilize one or more of thephysiological sensors.

Microcontroller

In one embodiment, a low power, high efficiency microcontroller 41, suchas a microcontroller from the RL78 family of microcontrollers offered byRenesas Electronics Corp., Tokyo, Japan, can be used. Architecturally,the microcontroller is built around a Harvard architecture thatphysically separates signal and storage pathways for instructions anddata storage. The microcontroller operates under a dedicatedmicroprogram stored as microcode within a non-volatile memory device,rather than a general purpose operating system, which aids in efficientoperation and longer power source life, although in a furtherembodiment, an operating system including a real time operating system,could be used. Note that there is memory located on the microcontrolleras well as externally and program instructions are expected to be storedin the microcontroller's flash memory.

Additional Components

The microcontroller 41 is interfaced to components, both integrated andoff-chip, that provide continuous and extensible monitoring capabilitiesto the IMD 10. A voltage regulation/charge control circuit 48 isinterfaced to the low frequency resonant charger antenna 47 and themicrocontroller 41, which together regulate and control the charging ofthe power source 49. An integrated Bluetooth system-on-a-chip (SoC)transceiver circuit 42 is similarly interfaced to the high frequencyantenna 34 and the microcontroller 41 to provide data communicationscapabilities to the IMD 10. An electrode dipole is formed by electrodes45 and 46, which are interfaced to an analog front end (AFE) 44 and tothe microcontroller 41 to effect electrocardiographic monitoring. In oneembodiment, temperature, actigraphy, and motion sensing are respectivelyprovided through a temperature sensor 50, Hall effect switch 51, andaccelerometer 52. Finally, monitoring data, including continuous ECGdata awaiting offloading, are stored in mass storage 53 in the form ofrandom access memory.

Paradigm

Purpose-build IMDs, such as implantable cardiac monitors (ICMs), arespecifically designed to address a range of potential conditions whichwould be observable over an expected patient population. Thus, typicalICMs require power hungry and complex signal filters, which are able todetect R-wave intervals on a very high percentage of the patientpopulation. Practically, however, the majority of the patient populationdoes not need extreme filtering. As a result, dramatic power savings arepossible if a signal filter could be selected that is appropriate for agiven patient and for patients with special needs, strong signalfiltering can be selected to reduce false positives at the cost of highpower consumption and frequent recharging.

Here, the IMD 10 implements a configurable hardware platform based on areprogrammable microcontroller that can be supplemented with additionalphysiological sensors, including an SpO₂ sensor, a blood pressuresensor, a temperature sensor, respiratory rate sensor, a glucose sensor,an air flow sensor, and a volumetric pressure sensor, andnon-physiological sensors, including an accelerometer and inertialmotion sensor. Through the microcontroller 41, the sensors can beselectively activated over the implantation lifetime, whether in realtime or during reprogramming, to tailor the monitoring of the patient toongoing diagnostic needs.

The microcontroller-based design also affords the flexibility to choosesignal filtering and processing algorithm options tailored to eachpatient. This microarchitecture allows the best patient experience byeliminating designs that adopt a one-size-fits-all approach and whichare dominated by considerations of accommodating the hardest cases. Themicroarchitecture further accommodates changes to patient morphology;modifications to the filtering software can be selected dynamically andupdated in the field as a configuration update that is pushed by aphysician from the “cloud,” that is, the server paradigm thatvirtualizes server-side functionality as a service widely availablethrough access to the internet or other wide-area data communicationsnetwork.

In a further embodiment, the transceiver 42 can be used in conjunctionwith the microcontroller to communicate with ingestible sensors, such asoffered by Proteus Digital Health, Inc., Redwood City, Calif. Ingestiblesensors are pills made of biocompatible materials, which combine remotemonitoring microelectronics with medication or inert materials that cansafely be taken by a patient. Typically, an ingestible sensor isactivated by gastric fluids dissolving or acting upon its surface, afterwhich the sensor begins to measure gastro-intestinal tract physiologyand, possibly, other types of physiology. Ingestible sensors that arecapable of communicating wirelessly, such as over Bluetooth, Medradio,or via WiFi, are available as a real-time-capable alternative tostandalone ingestible sensors that store recorded physiology onboard thedevice. This wireless-capable class of ingestible sensors allows thesensory data to be captured in real time. Moreover, these types ofingestible sensors aAcan be coupled with the IMD 10; thus, a patient canbe monitored for medication compliance by providing accurate,time-correlated data that can be used to evaluate non-adherence and toprovide positive reinforcement. The patient's caregiver can be notifiedin real time as to a patient's behavior with respect to adhering toprescribed medication.

The platform described facilitates the monitoring of every heartbeat incontrast to conventional non-rechargeable platforms, which typically donot have enough power to store and transmit each heartbeat. In additionto monitoring each heartbeat, since the heartbeats are offloaded, theheartbeats may be analyzed by an intelligent algorithm not located inthe platform proper, which allows for better recognition of arrhythmiasand disease conditions, as the complexity of the algorithm is notlimited by the amount of power available to the analyzing device.

The IMD 10 continuously monitors the patient's heart rate on aheartbeat-by-heartbeat basis and physiology. FIG. 13 is a flow diagramshowing a method 100 for continuously monitoring electrocardiography foruse in the IMD 10 of FIG. 1. Initially, following successfulimplantation, the microcontroller 41 executes a power up sequence (step101). During the power up sequence, the voltage of the power source 49is checked, the state of the mass storage (flash memory) 53 isconfirmed, both in terms of operability check and available capacity,and microcontroller operation is diagnostically confirmed.

Following satisfactory completion of the power up sequence, an iterativeprocessing loop (steps 102-114) is continually executed by themicrocontroller 61. During each iteration (step 102) of the processingloop, the AFE 44, through the electrode dipole created by electrodes 45and 46, continually senses electrocardiographic signals; additionally,patient physiology is sampled at appropriate intervals, depending uponthe sampling frequency selected for the particular type of physiologybeing sensed (step 103). One or more types of physiology can be sensedat any given time. The type and sampling rate of physiology areselectively activated over the lifetime of the IMD 10 via themicrocontroller 41 through programmatic control, which in turn,determines the hardware device being utilized. For instance, readingpatient temperature once each minute would require activation of thetemperature sensor 50. A similar approach to sensing non-physiologicaldata, such as position or posture, is followed mutatis mutandis.

A sample of the ECG signal and, at appropriate intervals, physiology,are read (step 104) by the microcontroller 61 by sampling the AFE 44 andappropriate physiology sensing hardware. Each sampled ECG signal andeach of the physiology signals, in quantized and digitized form, aretemporarily staged in a buffer (step 105), pending compressionpreparatory to storage in the mass storage 53 (step 106). Followingcompression, the compressed ECG digitized samples are again buffered(step 107), then written to the mass storage 53 (step 108) using thecommunications bus. Processing continues (step 114), so long as storagespace remains available in the mass storage 53, after which theprocessing loop is exited. Still other operations and steps arepossible.

The IMD 10 processes sensing signals generated by ingestible sensorsfollow a similar methodology as with processing monitored physiology,with two important distinctions. First, ingestible sensors are typicallyactivated upon ingestion and thereafter generate monitoring data onlyduring the time in which they are present in the patient's digestivetract. Second, ingestible sensor data is generally time-sensitive, wherethe correlation of the time of signal generation and time of day is ofnotable interest in itself, whereas physiological data is typically seenin the context of other physiological events, such as SpO₂, which issignificant with reference to cardiac events.

Concurrently, the IMD 10 can offload stored monitoring data to adatacenter or other external device. The data is offloaded in aconceptually-separate execution thread as part of the iterativeprocessing loop (steps 102-114) continually executed by themicrocontroller 61. If an offloading event occurs (step 109), the IMD 10connects to a mobile device (step 110), such as a smart phone orcellular-enabled tablet, and the stored samples are sent from the massstorage 53 to the mobile device (step 111). In turn, the mobile devicerelays the uploaded ECG and physiology samples to the datacenter.Alternatively, the IMD 10 can connect directly to the datacenter,provided the transceiver 42 is sufficiently capable. The mass storage 53is cleared (step 112) and the IMD 10 disconnects from the mobile device(step 113) upon completion of the sending of the stored samples.Processing continues (step 114). Still other operations and steps arepossible.

While the invention has been particularly shown and described asreferenced to the embodiments thereof, those skilled in the art willunderstand that the foregoing and other changes in form and detail maybe made therein without departing from the spirit and scope.

1. A system for patient medical care initiation based on implantablemedical device data with the aid of a digital computer, comprising: animplantable medical device, comprising: a housing on which a first and asecond electrode are formed; and a microcontroller circuitcircumferentially provided within the housing and comprising amicrocontroller operable under program instructions stored within anon-volatile memory device, further comprising: an analog front endelectrically interfaced to the first and the second electrodes andoperable to sense electrocardiographic signals; and a transceivercircuit operable to wirelessly communicate with a download station; theprogram instructions defining instructions for the microcontroller tocontinuously sample the electrocardiographic signals into thenon-volatile memory device and to offload the non-volatile memory to thedownload station via the transceiver circuit; the download stationconfigured to receive the samples from the transceiver circuit; at leastone computer, comprising: a database configured to store the receivedsamples and medical diagnostic criteria; and a processor and a memoryconfigured to store code executable by the processor, the processorconfigured to: generate a diagnostic overread of the samples using themedical diagnostic criteria; and initiate medical care of the patientwith one or more pre-identified care providers based on the overread. 2.A system according to claim 1, wherein the diagnostic overread comprisesone or more diagnostic findings that are rated by degrees of severity.3. A system according to claim 2, the processor further configured to:compare the ratings of the diagnostic findings to a threshold, whereinthe initiation of the medical care comprises generating orders to seekimmediate treatment based on the comparison.
 4. A system according toclaim 1, the processor further configured to at least one of: notify ageneral practice physician upon one of the diagnostic findingscomprising normal physiological data despite patient complaints of lightheadedness or syncope; notify a cardiologist upon one of the diagnosticfindings comprising atrial fibrillation of over 1 minute duration,ectopy comprising more than 3 PVCs per minute, palpitations comprisingfluttering of the chest, and supraventricular tachycardia comprisingheart rates over 180 bpm; and notify an electrophysiologist upon one ofthe diagnostic findings comprising ventricular tachycardia comprising 3or more consecutive abnormal ventricular beats, bradycardia comprisingpauses greater than 3 seconds, and heart blockage comprising thenon-conduction of any normal sinus beat.
 5. A system according to claim1, the processor further configured to: generate a referral to one suchcare provider if the diagnostic findings comprises a medical conditionnot found in the patient's medical history; and engage proactive healthcare management if the diagnostic findings comprises a medical conditionfound in the patient's medical history.
 6. A system according to claim1, the processor further configured to: obtain physiological dataassociated with a population of individuals similar to the patient,wherein the diagnostic overread is further generated based onphysiological data associated with the population of individuals similarto the patient.
 7. A system according to claim 1, wherein at one of: thereceived samples are structured along a temporal spectrum that reflectsa change in the received samples over time; and the received samples arestructured on a per event basis.
 8. A system according to claim 1,wherein each of the medical diagnostic criteria are associated with atleast one of a class of health conditions and a specific medicalcondition.
 9. A system according to claim 8, wherein the classes ofmedical conditions comprise cardiac disorder, respiratory distress,hypoglycemia, and hypoxia.
 10. A system according to claim 1, whereinthe implantable medical device further collects additional physiology ofthe patient and the diagnostic overread is further made based on theadditional physiology.
 11. A method for patient medical care initiationbased on implantable medical device data with the aid of a digitalcomputer, comprising: performing an electrocardiographic monitoringusing an implantable medical device, comprising: a housing on which afirst and a second electrode are formed and a microcontroller circuitcircumferentially provided within the housing and comprising amicrocontroller operable under program instructions stored within anon-volatile memory device, the microcontroller circuit furthercomprising an analog front end electrically interfaced to the first andthe second electrodes and operable to sense electrocardiographicsignals, the implantable medical device further comprising a transceivercircuit operable to wirelessly communicate with a download station, theprogram instructions defining instructions for the microcontroller tocontinuously sample the electrocardiographic signals into thenon-volatile memory device and to offload the non-volatile memory to thedownload station via the transceiver circuit; receiving by the downloadstation the samples from the transceiver circuit; storing by a databaseconfigured the received samples and medical diagnostic criteria;generating by a processor, the processor interfaced to a memory andconfigured to execute code, a diagnostic overread of the samples usingthe medical diagnostic criteria; and initiating by the processor medicalcare of the patient with one or more pre-identified care providers basedon the overread.
 12. A method according to claim 11, wherein thediagnostic overread comprises one or more diagnostic findings that arerated by degrees of severity.
 13. A method according to claim 12,further comprising: comparing the ratings of the diagnostic findings toa threshold, wherein the initiation of the medical care comprisesgenerating orders to seek immediate treatment based on the comparison.14. A method according to claim 11, further comprising at least one of:notifying by the processor a general practice physician upon one of thediagnostic findings comprising normal physiological data despite patientcomplaints of light headedness or syncope; notifying by the processor acardiologist upon one of the diagnostic findings comprising atrialfibrillation of over 1 minute duration, ectopy comprising more than 3PVCs per minute, palpitations comprising fluttering of the chest, andsupraventricular tachycardia comprising heart rates over 180 bpm; andnotifying by the processor an electrophysiologist upon one of thediagnostic findings comprising ventricular tachycardia comprising 3 ormore consecutive abnormal ventricular beats, bradycardia comprisingpauses greater than 3 seconds, and heart blockage comprising thenon-conduction of any normal sinus beat.
 15. A method according to claim11, further comprising: generating by the processor a referral to onesuch care provider if the diagnostic findings comprises a medicalcondition not found in the patient's medical history; and engaging bythe processor proactive health care management if the diagnosticfindings comprises a medical condition found in the patient's medicalhistory.
 16. A method according to claim 11, further comprising:obtaining by the processor physiological data associated with apopulation of individuals similar to the patient, wherein the diagnosticoverread is further generated based on physiological data associatedwith the population of individuals similar to the patient.
 17. A methodaccording to claim 11, wherein at one of: the received samples arestructured along a temporal spectrum that reflects a change in thereceived samples over time; and the received samples are structured on aper event basis.
 18. A method according to claim 11, wherein each of themedical diagnostic criteria are associated with at least one of a classof health conditions and a specific medical condition.
 19. A methodaccording to claim 18, wherein the classes of medical conditionscomprise cardiac disorder, respiratory distress, hypoglycemia, andhypoxia.
 20. A system according to claim 11, wherein the implantablemedical device further collects additional physiology of the patient andthe diagnostic overread is further made based on the additionalphysiology.